多线程编程之终止pthread线程

原文：点击打开链接http://blog.youkuaiyun.com/lovecodeless/article/details/23956975

        Pthread 是 POSIX threads 的简称，是POSIX的 线程标准 。

          终止线程似乎是多线程编程的最后一步，但绝不是本系列教材的结束。线程创建到线程终止，希望先给读者一个关于多线程编程的整体认识。

          1.终止Pthread线程:pthread_exit()

          参数：

          ret:地址指针，本质上是返回值写入的地址。

          终止线程是线程的主动行为，一个线程调用pthread_exit，终止线程自身。线程终止会释放线程特定数据，线程特定数据为线程专有。由于线程共享全局数据，故线程退出不会释放进程的全局数据。

         该函数返回值ret如何使用？返回值是调用的概念，那么只有在一个线程被另一个线程“调用”时返回值ret才起作用。这里“调用”不同于一般意义上的函数调用，一个线程等待一个线程可以理解为“调用”。如一个线程调用 pthread_join等待另一个线程终止。下面介绍等待线程终止函数pthread_join。

         2.等待线程终止:pthread_join()

         该返回值ret通过另一个函数pthread_join传递。等待线程终止pthread_join原型为：

等待线程终止pthread_join会阻塞调用线程，直到其指定的线程终止。pthread_join通过第一个参数：线程ID来指定线程。调用者调用pthread_jion等待一个特定线程终止，在这种情况下，调用者可能需要这个特定线程的返回值，pthread_join通过将value_ptr的地址赋值给特定线程的pthread_exit的ret获取返回值。

         3.pthread_exi与pthread_join牛刀小试：

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#include <stdio.h> #include <Windows.h> #include <pthread.h> #pragma comment(lib, "pthreadVC2.lib") //必须加上这句 pthread_t t1 ; //pthread_t变量t1，用于获取线程ID void * My_thread ( void * args ){ for ( int i = 0 ; i < 100 ; i ++ ){ printf ( "I am your thread , my ID is %d \n " , t1 ); } pthread_exit ( "I am over !" ); //终止时返回"I am over !" return NULL ; } int main (){ void * My_thread_ret ; pthread_create ( & t1 , NULL , My_thread , NULL ); pthread_join ( t1 , & My_thread_ret ); printf ( "main主线程从My_thread子线程获取的返回值：%s" ,( char * ) My_thread_ret ); Sleep ( 1000000 ); return 0 ; }

 来自CODE的代码片

exit_join.c

                  上面的例子主线程main调用pthread_join等待子线程My_thread线程终止，通过传递My_thread_ret地址获取子线程My_thread的返回值，最后在屏幕上输出获得的返回值。